Astell & Kern Dual DAC PEE51: great sound in a small package

The Astell & Kern Dual DAC (PEE51) is the DAP specialist’s take on the portable DAC that works with mobile phones and computers alike.

As you would expect from A&K, the DAC does look the business with its all-metal, Zinc alloy casing. It sports a classy finish in a colour they call titan, which is presumably a take on titanium. It’s a fairly slim, conventional-looking housing with a short USB-C cable to facilitate handling. A&K says the stiff, braided cable is reinforced with aramid fibre and can withstand up to 200N of tensile force. While I believe it can stand up to some rough handling, I wouldn’t want to keep bending it, day in, day out, in any case. After all, why tempt fate?

A dongle isn’t exactly the most elegant solution, especially when attached to a handheld device. But it certainly is the most compact one; any other method will make your mobile phone unwieldy, so you might as well take the lightest and smallest. At 28g it could stand to be lighter, but at the same time it’s nice to have the assurance of a solid metal housing. However, if you’re an iPhone user, then tough luck – the PEE51 is not officially supported. Even if it does, it would mean that you need USB-C to Lightning adaptor, and that’s just plain messy.

At the heart of the PEE51 is a pair of low-power, Cirrus Logic CS43198 D/A converters. As you would have guessed, it draws power from your device, so the upside is that it doesn’t need a battery on its own. The PEE51 can decode up to DSD256 and 32-bit/384kHz files. It, however, doesn’t support MQA decoding, so you while you can still play them, you won’t be able the get full dynamic range of those tracks. You need an app that allows for this, such as the Onkyo HF Player for Android, and you have to factor in that cost as well. Also, bear in mind that the storage requirements get more insane as the resolution goes up, much like RAW files in photography. A DSD256 file for a five-minute song is almost a gigabyte. Ah, then perhaps you might want to have a smaller file for your mobile and a larger one on your desktop then? Why have two copies? Should I get another player instead? Welcome to the audiophile world.

In my opinion, the baseline, high-resolution files (24-bit, 48kHz and up) are more than sufficient for the job, especially if you often listen on the move where there is plenty of background noise. If you have the luxury to listen to music in quiet spaces, then you can seriously consider better options. And since the Cirrus is rated to handle up to 600 ohm and is capable of 2 Vrms without load, it gives you a fair bit of options where headphones are concerned.

The PEE51 is a considerable step up over stock DACs on your computers and mobile phones – it’s certainly far better than the one on my M1 MacBook Pro. The bass is far more pronounced and more detailed, even for lower quality audio sources like Youtube. I was surprised by the results from a Sennheiser HD650 ; the music is far punchier on the whole, while instruments in the mix have more presence and truly stand out. Your results may vary, of course: I much preferred the pairing of the HD650 over a technically superior Beyerdynamic T1. In this case, the HD650 felt punchier, and the presentation is far more balanced than with the T1, which felt loose on the low end while the trebles are relatively muted. But at the end of the day, it is also a matter of taste.

Is it justifiable to pay $189 for an Astell & Kern Dual DAC? In a nutshell, you can get a basic DAC from say, FiiO, for around $70 dollars that can decode 24-bit/96kHz files. It sounds pretty decent too – definitely a step up over stock – especially in a mobile setting where there is external noise that naturally detracts from a flawless listening experience. If you are just looking for an upgrade as opposed to looking for ’trouble’, my suggestion is to go budget; the offerings out there are pretty good.

That said, I did enjoy the A&K Dual DAC immensely, especially since I found a headphone+DAC pairing that I enjoyed. The law of diminishing returns is especially true in the audiophile world and often, the best way about it is to simply pick out what you love (and not simply something you like) for your budget, and not castigate yourself about the diminishing returns.